Prior to the installation of a cell tower for a mobile communication network, a candidate location must be characterized as to its suitability as a transmission site and a reception site. Current methodology consists of placing a directional antenna at the candidate location and then measuring the signal transmitted from the antenna at various locations around the candidate site. The elevation, azimuth, and amplitude of the candidate site coverage are computed from the geographic locations and signal strength measurements taken in the field.
Candidate cell sites are also characterized by the existing RF environment or interference at the site. Current methodology is to take measurements at the frequency and bandwidth of interest from the cell antennas installed at the completed site. Since the cell site antennas are mounted in fixed orientations, the originating direction of any resulting signals can only be known to a gross bearing. For example, if there are 3 directional cell antennas mounted at compass bearing 0, 120, and 240 degrees from North, then an offending signal received by one of these antennas can be thought of as coming from one of those bearings. If further clarification is needed, the antenna with the strongest offending signal level could be rotated until the signal level is measured to be at a maximum. Then, the compass bearing to the source of the signal can be determined. One of the disadvantages of this method is the possibility of detecting a peak signal level in a side-lobe of the directional antenna instead of in the main lobe, thus leading to a false directional reading.
Similarly the antenna angle with respect to the horizon could be adjusted to find the maximum value and the elevation (or declination) of the offending signal. The signal measurement device is typically a level meter or a spectrum analyzer that indicates the amplitude of the signal. It does not have a display which incorporates azimuth and elevation information from the orientation of the antenna.
Accordingly, there is a need for a system for quickly displaying not only the amplitude of the signal but also azimuth and elevation of the signal.